As is known to those skilled in the art to which the invention pertains, trailer assemblies have been provided with innovations and accoutrements, designed to facilitate the transfer of a load. However, little attention has been paid to the driving of the assembly when the trailer is either unloaded or only partly loaded. Additionally, little attention has been paid to working within a trailer that may not have enough room for one to stand up in. Also little attention has been made to allowing for relatively simple retrofit of an existing flat trailer such that the flat trailer can be made into a variable height trailer.
Present day trailers, generally, have standard size frames with fixed height sidewalls. This inherently creates problems. For example, current fixed height trailers do not allow the variability in height required to tow different sized cargo. Consumers must either purchase a low trailer that is very difficult for a user to maneuver about inside and can only fit a specific height cargo, but is more efficient to tow, or consumers must purchase a trailer that is tall enough to tow different height cargo and that allows one to move around and/or work inside, but is very inefficient to tow. The latter also results in towing dead air space a majority of the time.
Furthermore, the air resistance about the trailer is constant due to the fixed height trailer walls. By being able to shorten the height of the walls and, therefore, the area thereof the resistance to air is reduced thereby giving somewhat increased fuel mileage and much less cross wind buffeting. Additionally, if one has to work in a trailer that is carrying vehicles, such as snowmobiles, ATV's, or motorcycles, it may be very difficult to service or otherwise work on the vehicles if the trailer roof is too low. Also lower style trailers currently being marketed have ramps that are difficult or impossible to load certain types of cargo due to the steep angle of a short ramp. Current ramps being marketed on these fixed height trailers are only as long as the height of the wall of the trailer.
For all of these reasons, a benefit to the art would be provided by a trailer having an extensible and retractable roof with folding ramps. It is to this to which the present invention is directed.